Joy is an emotion that many people seek to experience, but Dr. Brené Brown says it often brings with it a feeling of terror. In this clip from “Super Soul Sunday,” which airs on Sundays at 11 a.m. ET on OWN, the renowned research professor talks to Oprah about what her research, interviews and experiences have taught her about joy.

“I was so off base before I did this: I made a commitment to everybody I know. I said, ‘I will never talk about joy for the rest of my career without talking about gratitude,” Dr. Brown tells Oprah in the clip. “I have never interviewed a single person who talks about the capacity to really experience and soften into joy who does not actively practice gratitude.”

Dr. Brown also admits that there’s a very tricky element involved with this emotion. “If you ask me what’s the most terrifying, difficult emotion we feel as humans,” she says, “I would say joy.”

Calling joy “terrifying” may seem strange, but Dr. Brown explains that the fear stems from having our joy taken away. “How many of you have ever sat up and thought, ‘Wow, work’s going good, good relationship with my partner, parents seem to be doing okay. Holy crap. Something bad’s going to happen'?” she asks the audience. “You know what that is? [It’s] when we lose our tolerance for vulnerability. Joy becomes foreboding: 'I’m scared it’s going to be taken away. The other shoe’s going to drop…' What we do in moments of joyfulness is, we try to beat vulnerability to the punch.”

To illustrate this point, Dr. Brown shares with Oprah a poignant story about a man she interviewed who admitted to her that he never allowed himself to be too joyful about anything in life. Then his wife of 40 years was killed in a car accident. Dr. Brown remembers him saying, “The second I realized [my wife] was gone, the first thing I thought was, ‘I should have leaned harder into those moments of joy. Because that did not protect me from what I feel right now.’”

Truly joyful people, Dr. Brown says, do not allow fear to take away from fully experiencing joy. “They don’t say, ‘That’s a shudder of terror about feeling joyful. I’m going to dress-rehearse tragedy,’” she says. “They say, ‘I’m going to practice gratitude… Gratitude is a practice. It is tangible.’”